The ecological adaptability of pinewood nematode populations: survival strategies, mechanisms and co-evolution

Bursaphelenchus xylophilus (pinewood nematode, PWN) is the causal agent of pine wilt disease and ranks among the most destructive invasive pests threatening global forest ecosystems. Since its introduction to China, this nematode has triggered massive ecological and economic losses, while its distribution range continues to expand northward. The association between the widespread dispersal of B. xylophilus in invaded areas and the ecological adaptability of its populations has drawn considerable attention.

This review systematically synthesizes recent research advances regarding the ecological adaptability of PWN populations, elaborating on molecular mechanisms and ecological strategies that enable the nematode to colonize novel environments. In terms of thermal adaptation, differentially expressed genes, small heat shock protein families and the accumulation of key metabolites collectively shape adaptive pathways to resist extreme high and low temperature stress. For host adaptation, PWN displays polyphagous feeding habits and relies on diverse arboreal fungi as nutritional resources when pines were weakened or died. Detoxification enzyme cascades and effector proteins enable the nematode to counteract host defensive metabolites. Specifically, effectors suppress host peroxidase activity, thereby quenching reactive oxygen species bursts and disrupting plant hormone regulatory pathways to attenuate pine immune responses. Co-evolutionary interactions between PWN and vector beetles manifest across multiple dimensions, including synchronized life cycles, specialized dispersal-stage juveniles, and infochemical-mediated interspecies communication. PWN also forms intricate interaction networks with associated fungi and bacteria, which exert vital functions in nutrient acquisition, pathogenicity enhancement and terpenoid degradation. Notably, ascaroside pheromones serve as central signaling molecules that modulate interspecific competition and reproductive phenotypic plasticity. Population genetic analyses have uncovered shifts in genetic diversity, regulatory pathways governing population structure and reproductive efficiency, as well as synergistic evolutionary correlations between invasive population genetics and pathogenicity. Multi-omics analytical frameworks provide novel perspectives for dissecting the adaptive evolution of PWN.

The invasive success and widespread dispersal of B. xylophilus are fundamentally driven by its strong population ecological adaptability. Finally, this review summarizes the existing research gaps and proposes future research priorities alongside targeted pest management strategies. © 2026 Society of Chemical Industry.